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Tunnel Marking Issues, Traffic Lane Dividers, and More

Tunnels comprise an ever-increasing percentage of the amount of roadway in developed nations.  In fact, in many instances, such as traversing mountainous areas, bypassing large cities, or driving from Great Britain to the European continent, tunnels are the only practical means available for conveying vehicular traffic.  At the same time, the unique environment in highway tunnels exposes them to a number of potential hazards, making the use of traffic lane dividers and other safety measures especially important.

Risks inherent to tunnel environments

As a whole, road tunnel travel is remarkably safe.  However, when problems do occur, their significance is magnified by a number of unique factors.  These include:

  • Dependence on artificial lighting – Except for the shortest tunnels, sunlight and vehicle headlamps alone do not provide sufficient illumination.  Networks of overhead lights, sometimes many miles long, must be maintained at all times to prevent accidents.  This makes tunnels especially vulnerable to disruptions in the power grid.
  • Limited clearances – When an accident occurs on an above-ground road, there is usually sufficient space to allow plenty of room for emergency responders, remove accident-related debris, and permit normal traffic patterns to resume within a reasonable period of time.  However, when a wreck occurs within a tunnel, space is at a premium, significantly increasing the risks to police and medical units, as well as to motorists. 
  • Lack of alternative routes – With most public roadways, shutting down one section simply means detouring traffic to the next available route.  This is rarely possible with tunnels, however, as they normally go through areas where other roads are either rare or non-existent.  For example, should the tunnel between Great Britain and the continent be shut down for any reason, drivers can hardly be expected to ford the Channel in their motor vehicles, nor can ferries make up for the access the tunnel alone provides.
  • Lack of communications – In most cases, should a motorist experience mechanical trouble or be involved in an accident, then he or she can use a cellular phone to summon assistance.  This is rarely possible in tunnel environments, however.  It may take hours to summon help to the scene, during which there is a greatly increased risk of crashes or other problems that may cause significant loss of life, property damage, or interruption of normal traffic patterns.

Mitigating the risks of tunnel accidents

All of the above factors point to the fact that highway engineers and public safety officials must exercise special precautions to ensure the smooth flow of traffic through roadway tunnels.  Some means of doing so include the following measures:

  • Using highly reflective signage, such as types made with prismatic and/or fluorescent materials, to maximize visibility.
  • Installing traffic safety measures, such as frequent call boxes from which help may be summoned to the tunnel with a minimum of delay.
  • Using backup power sources to maintain lighting.  These can include solar panels and batteries or diesel generators.
  • Alerting drivers to upcoming tunnels well in advance, so that they may prepare for the change in environment.
  • Using highly retroreflective materials for pavement markers as well as signage.
  • Making permanent signs larger and using them more frequently than in above-ground situations, to further compensate for limited amounts of light.
  • Keeping maintenance and construction activities within tunnels to an absolute minimum, as well as conducting them only during minimal usage times.
  • Training motorists in issues of tunnel safety, including the need to be at a heightened state of alertness while driving through tunnels, keeping headlamps on at all times, etc.

Tunnel construction will only increase as the earth becomes increasingly urbanized.  This will lead to greater challenges for highway engineers, but with planning and foresight, public safety and normal traffic patterns can be maintained.